Jia Zhangke’s gangster epic is a twisting tale of love and survival in 21st-century China.

“Ash Is Purest White,” Chinese auteur Jia Zhangke’s most serious foray into the gangster genre since “A Touch of Sin,” is a winding tale of love, disillusionment and survival that again represents his vision of his country’s spiritual trajectory.

At 141 minutes, the work has its intellectually ponderous moments but is ultimately saved by Jia’s muse and wife, Zhao Tao, who surpasses herself in a role of mesmerizing complexity.

More expository and down-to-earth than usual, Jia delves deep into the protagonists’ most vulnerable feelings as they pay dearly for both sin and honor.

Cinephile anticipation for anything helmed by the onetime Godfather of Chinese independent cinema will give this Chinese-French co-production a forceful push into Euro-art-house territories. Domestic response may depend on whether the work nabs any awards at Cannes, as in the case of the Berlin Golden Bear winner “Black Coal, Thin Ice,” which starred “Ash” leading man Liao Fan.

Jia said in an interview that his idea for “Ash” sprang from reassessing the romantic arcs cut out of his “Unknown Pleasures” and “Still Life.” The central figure, Qiao, can be seen as a reinvented composite of the female protagonists from those films. Thus, the first and second part of the story are set in Datong and Fengjie, the respective locations of the two films.

The Chinese title “Jianghu Er Nv” (Sons and daughters of Jianghu) refers to members of the underworld but also alludes to people who uphold a sense of righteousness despite coming from a shady or poor background. The word jianghu (river and lake) was used in classical wuxia literature to denote the world of martial arts. It has paradoxical connotations of brotherhood or code of honor and power-driven strife. In “Ash,” jianghu stands for the lifestyle the protagonists have chosen and also embodies the conflicting views they hold about society.

Bookended by mahjong games, the story spans the 18 years of the 21st century, starting in and coming full circle to Datong. Qiao (Zhao) is the girlfriend of Bin (Liao), a provincial mobster who likes to think of himself as a big fish in a small pond. Part of a generation raised on Hong Kong triad films, he takes pride in living by jianghu rules and enjoys helping local businessmen and rival gangs settle scores. Jia captures the restless appetite of an era whose cocky excess is epitomized in a scene when Bin and his cohorts empty a smorgasbord of hard liquor into an enamel wash basin and drink toasts to swear loyalty. The helmer’s homage to John Woo’s brand of heroic bromance is represented by Taiwanese singer Sally Yeh’s theme song from “The Killer,” which drifts through the film like a time capsule.

However, change is apace, symbolized by the sudden and unstoppable rise of young punks who challenge the not-even-so-old order. Unglamorous but vicious, they render Bin helpless in an ambush of shockingly visceral violence (recalling scenes in “A Touch of Zen”). Forced to interfere to save his life, Qiao gets sentenced to five years in jail. Upon release in 2006, she goes looking for Bin, which takes her all the way to Fengjie, a city among the Three Gorges that faces imminent submersion.

Echoing the timelines and three-act structure of “Mountains May Depart,” “Ash” also parallels Jia’s last feature in that the couple drift apart after the first flush of youth and optimism. But while the divorcée (also played by Zhao) in “Mountains” remains a passive observer of her own fate caught in her country’s monumental leap forward, Qiao takes charge of her life with the desperation and resourcefulness that make her an icon of the Chinese can-do spirit. How she takes to scamming after being scammed makes this the most riveting chapter of the film, which offers a humane angle on survival in a time of incredible flux. In her own words, she’s resorted to the tricks of jianghu to reach Bin, who, ironically, no longer belongs to it.

When she finally tracks him down – her (and the audience’s) sense of betrayal or longing for vindication is overshadowed by the unanticipated pathos he exudes. As she embarks on further journeys and drifts into new encounters, another reunion with Bin in the last act takes place in the present, 12 years later. Their new relationship again redefines the concept of jianghu, as a sense of duty and resignation, shorn of the earlier romanticism and adventurousness. Although the last stretch is too long, the dramatic situation and characters’ emotions are far more authentic and moving than, say, the artificial futuristic setting in the third act of “Mountains.” And the conclusion that people are tied to their roots for better or worse is a point that has universal resonance.

The choice of Liao (“The Master”) as Zhao’s co-star results in one of the best screen pairings in the director’s films. Sporting a mustache that oozes sleaziness, Liao is one of the few mainland actors who would play a scoundrel and abusive male without reserve (see “Ocean Flame”). While his intensity can be overwrought, it’s held in check by Zhao’s poised aura. On the other hand, the casting of renowned directors Feng Xiaogang, Diao Yinan, Zhang Yibai and Xu Zheng in cameos is more like a vanity gesture, as those roles could have been played by any actor.

Tech credits, mostly by a French crew, are top-drawer. French DP Eric Gautier (“A Christmas Tale,” “The Motorcycle Diaries”), who took over lensing duties from Jia regular Yu Lik-wai, makes transitions from DV (in Academy ratio) to Digibeta, HD video, film and Redweapon cameras feel seamless to lay audiences while creating different textures for the changing time periods.

Qiao is in love with local mobster Bin. During a fight between rival gangs, she fires a gun to protect him. Qiao gets 5 years in prison for this act of loyalty. Upon her release, she goes looking for Bin to pick up where they left off. A story of love, betrayal and loyalty set in China’s underworld.Production: (China-France) A Shanghai Film Group, Xstream Pictures, Huanxi Media Group (Taizhou), Huanxi Media Group (Tianjin), MK Productions production. (International sales: MK2 Films, Paris.)